The application targets cognitive mechanisms underlying persistence of behavioral problems classified as ADHD in adolescence and early adulthood. It builds on [a] prior work on children and young adults with ADHD, and [b] well established vision and language research programs at MSU, to advance integrated research using state of the art cognitive paradigms to access executive dysfunction in persistent ADHD. ADHD represents a major public health problem, and the poor long term outcomes of a substantial group of these children into adolescence and adulthood are a growing focus of concern, including auto accidents, substance abuse, criminality, and occupational problems. Cognitive mechanisms that might mediate this persistence are under-examined in adolescents and adults, and have been poorly captured with traditional neuropsychological studies. Conceptualizing ADHD as reflecting a core inhibitory or regulatory dysfunction, and conceptualizing the inhibitory domain as comprising executive and automatic functions in both cognitive and output processes, the proposed work has three related aspects. First, it aims to better establish subtype deficits in adolescence and adulthood using traditional "molar" executive function measures. Secondly, it provides for a detailed study of several kinds of inhibition in language processing and production. The application to ADHD of these basic cognitive science paradigms is novel and represents an implementation of the translational research priority recently established at NIH. Adolescents (age 14-17) and young adults (age 18-30) with ADHS and matched controls will be recruited via a population based multi-stage screening procedure and will then complete laboratory cognitive tasks. The procedures cover methods previously utilized with ADHD children (such as the anti-saccade paradigm) as well as several cognitive tasks either under-utilized or never utilized with any ADHD populations. Successful completion of the objectives can help isolate cognitive dysfunctions that may mediate persistence of ADHD symptoms, thus providing critical information concerning validity of the adult syndrome, and providing clues to etiology and to eventual prevention for persistent ADHD.